Dental eruption chronology in degus (Octodon degus).

The purpose of this study was to gain information concerning chronology of postnatal dental eruption in degus (Octodon degu). Specific findings pertain to the estimation of postnatal age at tooth emergence through the gingiva and to the age when a particular tooth is in functional occlusion. Fifty newborn degu pups were included in this study. The oral cavity endoscopy was carried out under isoflurane anesthesia in all animals 3 to 4 and 24-hours after birth, then at 1-day intervals until the age of 40-days, and subsequently at 2-day intervals until 75-days of age. Tooth emergence was considered to have occurred when any portion of the crown had penetrated the gingiva. The stage when the teeth come into occlusion was defined as the functional occlusion. The degus were born with completely erupted permanent incisors that were already in functional occlusion. All the premolar teeth and all the first molar teeth erupted on days 2 - 3 and 4 - 5 of life, respectively. The first signs offunctional occlusion ofall the first 2 cheek teeth were observed on days 9 - 11. Maxillary and mandibular second molar teeth emerged between days 17 - 19 and 18 - 20, respectively. First signs of functional occlusion were observed on days 30 - 31 and 31 - 33for maxillary and mandibular second molar teeth, respectively. Maxillary third molar teeth emerged on days 38 - 44 and erupted into occlusion on days 48 - 58. Mandibular third molar teeth emerged on days 39 - 46 and erupted into occlusion on days 58 - 72.